1. Field of the Invention
This invention relates, generally, to methods for improving the grammar of the final translation of a machine-translated sentence.
2. Description of the Prior Art
Different languages follow different rules of grammar. Thus, a sentence that is perfectly grammatical in the sentence to be translated, i.e., the source language, may become ungrammatical after translation into the target language if the translator does not apply all of the grammatical rules of the target language.
Thus, when machine translation is performed, the machine must know the grammatical rules of the source language and the target language if the final translation is to be grammatically correct. However, the rules of grammar are so vast that heretofore it has been the conventional wisdom that machine translations will always be somewhat less than grammatically perfect.
Research groups in the United States, Japan, the Peoples Republic of China (mainland China), the Republic of China (Taiwan), Canada, Singapore, and Hong Kong have been working for about thirty five years on the problem of translating Chinese into English and other target languages. About four different categories of translation sophistication have been achieved.
In Category 1, each Chinese character in a Chinese sentence is translated into its equivalent word in the target language; the result, as is well-known, can be and usually is nonsensical.
Category 2 devices produce pidgin English, a fractured language that can be understood by English speakers but which is replete with awkward and unusual expressions. Thus, the translation is much better than the translation produced by a Category 1 device, but it is still unacceptable because it requires that the user of the sentence complete the translation by amending it as required by the rules of English grammar and syntax.
Category 3 devices simply pre-store refined English sentences in a memory and reproduce said stored sentences upon recognition of a Chinese sentence having the same meaning. These systems may be used to convert entries in a Chinese menu into refined English, to convert very often-repeated Chinese expressions into refined English, and the like. Thus, they have some utility to travelers and students having a very rudimentary need for translations, but they are impractical as general use translation machines because every language contains practically an infinity of different sentences, of course.
The CITAC machine translator, disclosed by the present inventor in U.S. Pat. No. 5,224,040, entitled "Method For Translating Chinese Sentences," and the present invention are Category 4 devices in that they are general use translation machines which provide meaningful, non-pidgin-type translations and refined, grammatically correct sentences, respectively.
At the time the present invention was made, it was not obvious to those of ordinary skill in this art how improved Category 4 machines could be made, in view of the prior art considered as a whole.